The present invention relates to mitral valve prosthetic devices and, more particularly, to platforms into which mitral valve prosthetic devices may be deployed via a transcatheter approach.
The use of a catheter-based percutaneous valved stent has been shown to be feasible in replacing in humans both the pulmonic and the aortic valves. The pulmonic valve was the first to be successfully replaced by a percutaneous approach and is the furthest along in development. There are currently two aortic valve products in clinical trials and more in development that are deployed percutaneously.
In addition to the percutaneous catheter-based aortic valve replacement devices there are three other types of replacement valve prosthesis known to the applicants that use different technologies. One known technology, named the Transcatheter Mitral Valve Implantation (TMVI), is being developed by CardiAQ Valve Technologies (CVT). This design is fundamentally a shape memory stent. A second known technology is being developed by EndoValve. The EndoValve design is not stent based but relies on a tripod anchoresk system with a central supporting strut. A device to be used with this technology will be introduced by minimally invasive surgical techniques. A third known minimally invasive mitral valve replacement device is being developed by the University of Kiel in Germany. Their design is stent based but requires placement through the apex of the left ventricle (LV), which can be relatively dangerous particularly in patients with CHF and IMR.
There are also a large group of percutaneous mitral valve repair devices that have been developed to date. The majority of these devices have tried to exploit the proximity of the coronary sinus to the mitral valve annulus to perform some type of “annuloplasty” to limit mitral regurgitation. The basic premise behind all of them is to place a device in the coronary sinus that will shrink the valve orifice and thus decrease mitral regurgitation. However, many of these systems are still under development, and are difficult to implant.
There is a substantial need for percutaneous mitral valve replacement technologies that are appropriately configured to account for the dimensions and geometry of the mitral valve. It would be advantageous to have a device that can be deployed percutaneously and/or transapically to create a platform at the mitral valve position that reduces the diameter to an appropriate and uniform size for subsequent percutaneous or transapical implantation of a valved-stent.
The present inventors have addressed the above needs by providing for a mitral valve prosthesis that may be percutaneously or transapically deployed in at least two stages. In a first stage, the subject of the present invention, a mitral annular platform adapted for percutaneous or transapical delivery is delivered to and anchored in the mitral valve annulus. In the second stage, which may include a known valved-stent mitral valve prosthetic device adapted for percutaneously or transapical delivery may be delivered to the mitral valve annulus for mounting in the mitral annular ring platform. The approach adopted by the present invention provides a consistent platform, and this may subsequently be used for accepting valved-stent mitral valve prosthetic devices from different vendors.
Introduction to delivering an implant within the heart.
By way of introduction to the field of the invention, and referring to FIG. 1, the heart 102 is a pump, the outlet of which is the aorta, including the descending aorta 104, which is a primary artery in the systemic circulation. The circulatory system, which is connected to the heart 102 further comprises the return, or venous, circulation. The venous circulation comprises the superior vena cava 108 and the inferior vena cava 106. The right and left jugular veins, 110 and 112, respectively, and the subclavian vein 114 are smaller venous vessels with venous blood returning to the superior vena cava 108. The right and left femoral veins, 116 and 118 respectively, return blood from the legs to the interior vena cava 106. The veins carry blood from the tissues of the body back to the right heart, which then pumps the blood through the lungs and back into the left heart. The arteries of the circulatory system carry oxygenated blood (not shown) from left ventricle of the heart 102 to the tissues of the body.
FIG. 2, is a cross-sectional illustration of the heart 102, showing the atrial septum 504. The distal region 302 of a catheter 300, substantially located within the right atrium 202, is shown with its longitudinal axis perpendicular to the atrial septum 504. The distal sheath 304, surrounding the catheter 300 is shown resident within the inferior vena cava 106. A septal penetrator 500 is shown extended through a puncture 502 in the atrial septum 504 and is routed into the left atrium 404. The septal penetrator 500 is a needle or axially elongate structure with a sharp, pointed distal end. The septal penetrator 500 is actuated at the distal end of the catheter 300. The septal penetrator 500 is operably connected to a control mechanism such as a button, lever, handle, trigger, etc., which is affixed, permanently or removably, at the proximal end of the catheter (not shown) by way of a linkage, pusher rod, or the like that runs the length of the catheter. Penetration of the septal wall 504 is known in the art, and may be used to position an implant such as a prosthetic mitral valve 410 in a manner that is shown in FIG. 3 wherein the existing leaflets 402 of the mitral valve are pushed aside and the exemplary prosthetic mitral valve 410 is deployed, thereby totally disabling the natural leaflets.
Thus it is known how to position a distal tip of a delivery catheter above the mitral valve of a patient through minimally invasive means. The present invention uses such known methods and systems, and uses them as described below in order to address shortcomings noted in the prior art with regard to placement of a mitral annular platform.